Harmonic resonance

But w hen the third and/or second harmonics are also present in the system, at a certain fault level it is possible that there may occur a parallel resonanee between the capacitor circuit and the inductance of the system (source), resulting in very heavy third or second harmonic resonant currents, which may cause failure of the series reactor as well as the capacitors. In such cases, a 6% reactor will not be relevant and a harmonic analysis will be mandatory to provide more exacting filter circuits. 

Vibration peaks at specific speed. Harmonic resonance Same as critical or resonance... 

Multiples of running frequency Harmonic resonance Multiples of component natural frequencies (rotor casing, foundation, bearing housing, diaphragms, etc.)... 

The following expression presents a different way to find the harmonic resonance frequency ... 

Figure 3.4 Shear displacement profiles across the resonator thickness for the fundamental and the third-harmonic resonances. (Reprinted with permisuon. See Ref. [9]. > 1991 Ameri-...

It is known that the position of the Raman D-band shows excitation energy dependence [44]. The 790- and 395-nm excited D-bands indeed appeared around 1,300 and 1,390 cm , respectively [27]. According to the D-band position in the HRS spectmm, both fundamental and harmonic resonances to intermediated states were thought to contribute to the enhancement of the HRS intensity. Conversely, the G-band shape, which is decomposed into G" " and G , suggested the contribution of harmonic resonances to the transition. The observed HRS G -band was able to be fitted with Breit-Wigner-Fano (BWF) type line shape, which is characteristic in Raman spectra of metallic SWNTs [45]. 

Nonlinear optical properties have recently been observed for the polysilane (PhMeSi) 132, suggesting that polysilanes may eventually find use in optical technology. Irradiation of a thin film of the polysilane at 1064 nm gave rise to efficient third-harmonic generation, while irradiation at 1907 cm-1 produced no nonlinear signal. The third-harmonic resonance is believed to be due to a three-photon process, but its origin is uncertain. Farther research will undoubtedly be carried out on this new phenomenon. 

Insonation frequency is also an important parameter in contrast-assisted US, due to the ability of UCAs to act as harmonic resonators. Insonation at the resonant frequency can result in a scattering cross section in a free bubble of up to 3 orders of magnitude larger than the ctoss section of the bubble itself For UCAs, this substantially increases contrast enhancement. The resonant frequency of a free bubble can be approximated by... 

The vibration-rotation spectra and/or the rotational spectra in excited vibrational states provide the af constants and, when all the a/ constants are determined, the equilibrium rotational constants can be obtained by extrapolation. This method has often been hampered by anharmonic or harmonic resonance interactions in excited vibrational states, such as Fermi resonances arising from cubic and higher anharmonic force constants in the vibrational potential, or by Coriolis resonances. Equihbrium rotational constants have so far been determined only for a limited number of simple molecules. To be even more precise, one has further to consider the contributions of electrons to the moments of inertia, and to correct for the small effects of centrifugal distortion which arise from transformation of the original Hamiltonian to eliminate indeterminacy terms [11]. Higher-order time-independent effects such as the breakdown of the Bom-Oppenheimer separation between the electronic and nuclear motions have been discussed so far only for diatomic molecules [12]. 

Harmonic Resonance in Industrial Power Systems. IEEE Transactions on Power Electronics, p>p. 215-222, Vol. 15, No. 2, March, 2000 lEC 60364-1 (2001), Electrical Installations of Buildings - Part 1 Fundamental Principles, Assessment of General Characteristics, Definitions, 2001 lEC 61936-1 (2002), Power Installations Exceeding 1 kV a.c. - Part 1 Common Rules, 2002 IEEE Standard 141-1993, IEEE Recommended Practice for Electric Power Distribution for Industrial Plants... 

Any harmonic resonance of the large elements should be moved away from the resonance region of the small elements. 

P.C. Buddingh, Even Harmonic Resonance—An Unusual Problem, IEEE Paper No. PCIC 2002-11 (2002). A.G. Forster, IEEE Trans. Ind. AppL 1A-11(6), 716 (1975). 

Movement of a PBA within its mechanical guides will be amplified due to shock and vibration resonance or harmonic resonance. 

Adding capacitors, however, can introduce system distiirbances, including transient voltage, harmonic resonance and transient voltage magnification. 

Some of the harmonic resonance approaches may be alternatives to chemical force micros-... 

Colla, L., S. Lauria, and F. M. Gatta. 2007. Temporary overvoltages due to harmonic resonance in long EHV cables. International Conference on Power System Transients (IPST) 233, Lyon, France. 

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